Embedded star formation in the extended narrow line region of Centaurus A: extreme mixing observed by MUSE

Abstract

We present a detailed study of the complex ionization structure in a small (~250 pc) extended narrow line region (ENLR) cloud near Centaurus A using the Multi Unit Spectroscopic Explorer. This cloud is located in the so-called outer filament of ionized gas (about 15 kpc from the nucleus) where jet-induced star formation has been suggested to occur by different studies. We find that, despite the small size, a mixture of ionization mechanisms is operating, resulting in considerable complexity in the spatial ionization structure. The area includes two H II regions where star formation is occurring and another location where star formation must have ceased very recently. Interestingly, the extreme Balmer decrement of one of the star forming regions (H_alpha/H_beta~6) indicates that it is still heavily embedded in its natal cocoon of gas and dust. At all three locations a continuum counterpart is found with spectra matching those of O/B stars local to Centaurus A. The H II regions are embedded in a larger gas complex which is photoionized by the radiation of the central active galactic nucleus (AGN), but the O/B stars affect the spatial ionization pattern in the ENLR cloud very locally. In particular, in the surroundings of the youngest star forming region, we can isolate a tight mixing sequence in the diagnostic diagram going from gas with ionization due to a pure stellar continuum to gas only photoionized by the AGN. These results emphasize the complexity and the mixture of processes occurring in star forming regions under the influence of an AGN radiation. This is relevant for our understanding of AGN-induced star formation suggested to occur in a number of objects, including this region of Centaurus A. They also illustrate that these young stars influence the gas over only a limited region.

arXiv comment7 pages, 7 figures, 1 table, accepted for publication in A&A

References in corpus (20)

• The Host Galaxies of AGN
• Astrophysics Source Code Library
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• Mechanical Feedback from Active Galactic Nuclei in Galaxies, Groups, and Clusters
• Jet-induced star formation in gas-rich galaxies
• The Distance to NGC 5128 (Centaurus A)
• Radio Jets Clearing the Way Through a Galaxy: Watching Feedback in Action
• Relativistic Jet Feedback in Evolving Galaxies
• Triggered Star Formation in a Massive Galaxy at z=3.8: 4C41.17
• Minkowski's Object: A Starburst Triggered by a Radio Jet, Revisited
• Evolution of clouds in radio galaxy cocoons
• Nebular Attenuation in Hα-selected Star-forming Galaxies at z=0.8 from the NewHα Survey
• Triggered star-formation in the inner filament of Centaurus A
• Anomalous HI kinematics in Centaurus A: evidence for jet-induced star formation
• Galaxy-scale AGN Feedback - Theory
• The radio/optical alignment and the recent star formation associated with ionized filaments in the halo of NGC 5128 (Centaurus A)
• Star formation efficiency along the radio jet in Centaurus A
• The Complex North Transition Region of Centaurus A: A Galactic Wind
• The jet-ISM interaction in the Outer Filament of Centaurus A
• The outer filament of Centaurus A as seen by MUSE

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• Widespread star formation inside galactic outflows
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• Complex AGN feedback in the Teacup galaxy. A powerful ionised galactic outflow, jet-ISM interaction, and evidence for AGN-triggered star formation in a giant bubble
• Local positive feedback in the overall negative: the impact of quasar winds on star formation in the FIRE cosmological simulations
• A Recent Major Merger Tale for the Closest Giant Elliptical Galaxy Centaurus A
• The Close AGN Reference Survey (CARS): No obvious signature of AGN feedback on star formation, but subtle trends
• The jet/wind outflow in Centaurus A: a local laboratory for AGN feedback
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• The relation of cosmic environment and morphology with the star formation and stellar populations of AGN and non-AGN galaxies
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• The missing link: tracing molecular gas in the outer filament of Centaurus A
• AGN feedback in an infant galaxy cluster: the LOFAR-Chandra view of the giant FRII radio galaxy J103025+052430 at z=1.7
• Optical Detection of Star Formation in a Cold Dust Cloud in the Counterjet Direction of Centaurus A
• The globular cluster system of NGC 1316 IV. Nature of the star cluster complex SH2
• Physical conditions in Centaurus A's northern filaments I: APEX mid-J CO observations of CO-bright regions
• Hydrogen recombination near-infrared line mapping of Centaurus A with IRSF/SIRIUS
• QSOFEED: Investigating warm molecular, low- and high-ionization atomic gas in six type-2 quasars with GTC/EMIR